The invention relates generally to computer systems, and deals more particularly with remote control of a local processor console and an application program running on the local processor console, and parallel display of application panels on a remote processor console and the local processor console.
Heretofore, remote control of a local processor console and an application running on a local processor console has been provided by connecting a remote processor console to the local processor console via a telephone line, and sending a data stream representing the local processor console display to the remote processor console. For example, a prior art local processor console within an IBM System/370 computer system was remotely controlled by sending an IBM "3270" data stream to a remote (dumb) IBM 3275 terminal in addition to the local (dumb) IBM 3272 terminal. An IBM "3270" data stream is a data stream which directly controls the console display. The 3270 data stream comprises for each field on the screen, information defining the type of field, the location of the field and the content of the field, for example, an alphanumeric character. While this arrangement permitted remote control of the local processor console and parallel display on the local processor console and the remote processor console, the speed of presentation of display on the remote processor console is limited by the transmission speed over the telephone line. Because the remote processor console in this example is dumb and requires the 3270 data stream, a large amount of data must be sent from the local processor console to control the remote processor console screen. Therefore, the remote processor console is subject to slow operation.
In the same session of the aforesaid System/370 computer system, an operator at the remote processor console could enter data or commands through the remote processor console keyboard. In response, terminal hardware within the remote processor console determines which fields are changed and sends information defining only the changed fields to the local processor console. This information is in the form of a 3270 data stream. The application running in the local processor console then processes the information and takes appropriate action, for example, updating the local and remote processor console screens by sending the 3270 data streams for the entire screen or changed portions as appropriate.
The aforesaid local processor console is also used in a different session as a dumb terminal for controlling an application running in the System/370 host processor. During this session, the host processor communicates with the local processor console with the 3270 data stream.
Still another prior art IBM System/370 computer system comprises a host processor, a personal computer coupled to the host processor by a local area network or a telephone line, and a remote processor console coupled to the local personal computer by a local area network or a telephone line. The personal computer includes software to act as a communications manager to couple the host processor to the aforesaid remote processor console (or another remote console similarly coupled by a local area network or a telephone line). In this prior art system, the software is IBM's "Gateway" program. The host processor runs an application and transmits the 3270 data stream to the personal computer, and the communications manager routes the 3270 data stream to the proper remote processor console which then acts as a dumb terminal.
In another prior art system, IBM's 4381 computer system, an application running on a local processor console (serving a host processor) makes function calls to cause a display. The function calls are written in SPIL high-level language, and are received by a language interpreter in the operating system of the local processor console. The language interpreter breaks down the high-level calls into many corresponding low-level calls including the 3270 data stream (and an address of an error handling routine), which low-level calls are passed through a first common adapter code (CAC) program in the local processor console. The language interpreter then determines if a remote processor console coupled to the local processor console is operable, and if so, invokes a common communications adapter (CAC) program which is a second type of CAC program responsible for communicating with the remote processor console through a communication link. Then, the first CAC program sends the 3270 data stream to the second CAC program, and the second CAC program sends the 3270 data stream to a receiver at the remote processor console (an IBM 3275 dumb terminal). Then, the first CAC program in the local processor console transmits the 3270 data stream to the local processor console screen, and the receiver at the remote processor console transmits the 3270 data stream to the remote processor console screen. Also, in this IBM 4381 computer system, the remote processor console can receive inputs from the keyboard of the remote processor console, and keystroke information in the form of short encoded transmissions are sent directly to the local processor console. Then, the keystroke information is received by the local processor console which processes the keystroke information and generates a 3270 data stream to update the local console screen as described above.
The local processor console (a UC.5 computer) of the IBM 4381 computer system can be operated in either of two modes, a manual function mode or a host operating system mode. In the manual function mode, code running above the operating system in the local processor console controls the screens of both the local processor console and the remote processor console. Keyboard information can originate from either the remote processor console keyboard or the local processor console keyboard, and keyboard control was made from the respective processor console. The keyboard information passes through the language interpreter in the local processor console, and then the first CAC program in the local processor console to the application running in the local processor console. In the operating system mode, the operating system of the host processor controls both the screens. The 3270 data stream information originates from the host operating system and is passed to the local processor console through a local channel adapter including hardware and a third CAC program which stores the 3270 data stream in the processor console. Then, the 3270 data stream is sent to the local console screen and the remote processor console screen.
In another prior art system (prior art under U.S. law), IBM's 308X remote support system, an IBM UC.5 computing engine served as a processor console for a main frame computer and another system 370 main-frame computer provided remote control of the UC.5 computing engine. Screens were displayed almost simultaneously at both the UC.5 computing engine site and at the remote site. Each site included a collection of templates containing fixed information for the screens, and to make a display at the remote site, the UC.5 computing engine sent an identification of the desired template and variable data to be merged into the template. The remote site included a table to map the variable information into the proper locations in the template. While the storage of the collection of templates at the local and remote sites reduced the amount of data transfer, there were draw backs to this system. The UC.5 computing engine ran low level code that included a merged combination of single line application and control commands. There was a command facility that received display-related (and other) single line codes. Another facility determined if the remote site was operable. If so, these display-related commands were routed to the remote site to control the remote display. These commands also caused the same display at the local site. Thus, the body of code was specific to the application. Also, the collection of templates was included in the microcode at both sites and when a template required change, the microcode at both locations was rewritten to incorporate the change. Moreover, the templates could only accept variable data of predefined length.
A general object of the present invention is to provide efficient remote control of a local processor and an application running on the local processor, and parallel display of application panels on a local processor console and a remote processor console.
Another general object of the present invention is to provide remote control and parallel display of the foregoing object yet provide flexibility and standardization in the implementation.